Communications of the ACM

a Content ID. But I would realize that
not all Internet routers recognize that,
so I would include a second ID, which
is a Host ID. If the router does not un-
derstand the first one, it can look at the
second or third, and it will basically act
on the first one that it recognizes. For
backward compatibility, that last ID
could be an IP address.”
For security, XIA borrowed an idea
from a prior NSF-funded project, Ac-
countable Internet Protocol (AIP): in-
corporating a cryptographic ID in ad-
dresses so they can be authenticated
through a public-private key challenge.
Steenkiste says the project uses this
scheme so it does not have to rely on
key-management infrastructure, as
both NDN and MobilityFirst do.

He also explained how such embedded authentication allows duplication not only of content, but also of dynamic services like entire websites. “You could replicate services using a public key, but then you could end up replicating a private key on a lot of devices. In XIA, there is one public-private key pair for the global service; then, there are basic public key pairs with each instance. They are all tied together with a certificate that is issued by the service’s owner, not a global certificate authority. The instances cannot hand the service off to others because they cannot sign for it: their private keys are not authoritative.”

the Growth of everything

Three themes are consistent in these
projects’ approaches: the Internet is
growing in terms of not only numbers,
but also diversity; the current seven-
layer OSI model needs adjustment to
move it away from host-centric net-
working; security must be a first-order
concern in every data transaction, not
only at the endpoints. These changes
require fundamentally different ways
of thinking about networking from
those currently in play.

Yet for Internet users, the basic experience should remain the same. As PARC’s Edens put it when speaking of CCN, “The seven-layer model is getting pretty darn tired, but if we continue to solve the problems that we have set out to solve, you should be able to interact with the content network just like you interact with the Web. You ask for content, and you get it back — you do not care whether it is cached or comes from the original publisher. But with intelligent routers, you can have things like dynamic rerouting, error recovery, and broadcasting. You can put all these functions into the network as services.” Or, as NSF’s Fisher noted, “We never expected the FIA projects would replace the current Internet, although some project evangelists are motivated by that as a holy grail. In either case, these projects can have a very large impact. That is very exciting.”

Further Reading nSF Future Internet Architecture Project, national Science Foundation, http://www. nets-fia.net VnI (Visual networking Index) Mobile Forecast highlights, 2012-2017, Cisco Systems, Inc., http://www.cisco.com/web/ solutions/sp/vni/vni_mobile_forecast_ highlights/ index.html.

Raychaudhuri, D., Nagaraja, K., Venkataramani, A.

MobilityFirst: A Robust and Trustworthy Mobility-Centric Architecture for the Future Internet. Draft, August 2012. http:// mobilityfirst.winlab.rutgers.edu/documents/ MobilityFirst_paper_MC2R_v10.pdf

Zhang, L., Estrin, D., Burke, J., Jacobson, V., Thornton, J. D., Smetters, D. K., et al. (2010)

named Data networking (nDn) Project. PARC Tech Report 2010-003 nDn-0001, PARC.

Han, D., Anand, A., Dogar, F., Li, B., Lim, H., Machado, M., et al. (2012)

XIA: Efficient support for evolvable internetworking. Proc. 9th USEnIX nSDI.

Tom Geller is an oberlin, ohio-based science, technology, and business writer.

names and numbers can be domain-specific. “The name certification service is somewhat similar in spirit to what ICANN provides for domain names,” said Raychaudhuri, “but there’s no central authority, so you can accept any NCS that you trust. For a device that’s part of my car, the NCS could be the auto manufacturer.”

Raychaudhuri believes the use of practically inexhaustible GUIDs will prevent the sort of unstable and “ roundabout” process now needed to get mobile devices on the Internet. “If you have a smartphone, you get a private IP address from the cell provider, then there is a public IP address in a gateway at the boundary of the cellular network. That gateway is a potential bottleneck or single point of failure. With MobilityFirst, a mobile device does not have to go through the gateway. No matter what network you are connected to, the global name resolution in MobilityFirst will find your current location.”

Addressing unknown unknowns

MobilityFirst prioritizes issues of mo-
bile accessibility; NDN focuses on con-
tent. A third FIA-funded project takes
an agnostic approach in forecasting the
Internet’s needs. The eXpressive Inter-
net Architecture (XIA) project divides
Internet players into “principals” such
as hosts, content, services, and users.
While identifying such current princi-
pals, it acknowledges that tomorrow’s
Internet may have other types of prin-
cipals, and is built to adapt when they
appear. Whatever the principal type of
a network resource, XIA describes a way
to reach it directly through a new eX-
pressive Internet Protocol (XIP). As prin-
cipal investigator and Carnegie Mellon
University professor Peter Steenkiste
said, “If we look forward to 10 years
from now, are we really sure that con-
tent and services will be the hot com-
modity? That is absolutely not clear:
there might be a change in the types of
entities that people will want to send.”
Steenkiste described how an XIA
requestor packet could get a satisfying
response even when points on the net-
work do not understand its new-form
destination type. “The current Internet
thinks of packets as having a destina-
tion address with one type of ID, such
as an IP address,” he said. “In XIA, I
would request a piece of content with